Objectives: This study was undertaken to correlate the clinical and laboratory findings for both the diseases and gain some understanding in the challenges faced in the interpretation of these findings.

Methods: 296 patients with history of fever were tested for dengue and leptospirosis simultaneously using Pan-bio Dengue IgM capture ELISA and Pan-Bio Leptospira IgM ELISA. Based on the test results, the patients were divided into 4 groups and all records studied for comparable clinical and laboratory data.

Results: 6.7% of the patients were found to seropositive for both dengue and leptospirosis. Fever, myalgia, headache, jaundice, nausea and vomiting were the commonest presentations accompanied in lower frequency by thrombocytopenia, hepatomegaly and raised transaminases. Hemoconcentration (44.8%) and thrombocytopenia (55.5%) were observed with dengue fever. 10.8% of patients with leptospirosis presented with thrombocytopenia.

Other co-infections and underlying conditions included Hepatitis A E and B, enteric fever and complications as Multiorgan failure, Pneumonia and Altered sensorium.

Conclusions: Many cofactors such as acute renal failure altered sensorium and severe hemorrhagic episodes were found to be the cause of increasing morbidity and similar clinical presentations which often confounded the judgment for early management. More analysis is required to find the cause of cross-reactivity between the ELISA kits for different infections for use in endemic regions.